A fingerprint recognition module has gradually become one of standard configurations for a portable electronic device. A user may perform identity identification by using a fingerprint recognition module, to unlock the portable electronic device, or to execute an application.
A detection mode of the fingerprint recognition module may be divided into a capacitive fingerprint sensing technology and an optical fingerprint sensing technology. In the prior art, settings of an optical fingerprint recognition module are shown in FIG. 1A and FIG. 1B. FIG. 1A is a sectional view of a portable electronic device in the prior art. FIG. 1B is an enlarged view of an area A in FIG. 1A. In FIG. 1A, the portable electronic device 20 includes: a touch panel 21, a display module 22, an optical fingerprint sensor module 23, and a housing 24. The housing 24 is combined with the touch panel 21 to form a closed accommodating space, and is provided with and used for accommodating an electronic component (not shown) inside the portable electronic device 20. The optical fingerprint sensor module 23 includes an optical fingerprint sensor chip 231, and a layer of ultraviolet (UV) curable optically clear adhesive (OCA) G may be formed on a surface of the optical fingerprint sensor chip 231, to bind and fix the optical fingerprint sensor module 23 under the display module 22 by using the UV curable OCA G. On the other hand, an epoxy resin (epoxy) E may be coated on a junction of the optical fingerprint sensor chip 231 and the display module 22, to increase structural strength of the combination of the optical fingerprint sensor module 23 and the display module 22. However, the UV curable OCA G between the optical fingerprint sensor module 23 and the display module 22 easily spreads to another non-adhesive area on a surface of the display module 22 after being pressed. Moreover, if the optical fingerprint sensor module 23 is under uneven pressure during adhesion, a thickness of the UV curable OCA G is easily made uneven. Consequently, the optical fingerprint sensor chip 231 is twisted and cannot be smoothly adhered to the surface of the display module 22, causing the optical fingerprint sensor chip 231 to produce some errors when receiving light. On the other hand, the epoxy resin E coated on the junction of the optical fingerprint sensor chip 231 and the display module 22 may also spread to an area provided with the UV curable OCA G or the surface of the optical fingerprint sensor chip 231, affecting an effect of image capturing of a fingerprint feature by the optical fingerprint sensor chip 231.
In view of this, how to reduce a probability of twisting when an optical fingerprint sensor module of a portable electronic device and a display module are bound together, and prevent an epoxy resin used for increasing structural strength from spreading to an area provided with a UV curable OCA and a surface of an optical fingerprint sensor chip are technical problems to be resolve by the present invention.